Downhole Tool having Slips Set by Stacked Rings

ABSTRACT

An apparatus installs downhole in a surrounding tubular. A first shoulder on a mandrel of the apparatus is movable toward a second shoulder. A plurality of stacked rings are disposed about the mandrel and are spaced between the first and second shoulders. A first of the stacked rings decreases in spacing in response to the movement of the first shoulder toward the second shoulder, and a second of the stacked rings expands outward from the mandrel in response to the decrease in spacing. A slip disposed on the stacked rings is movable away from the mandrel toward the surrounding tubular in response to the outward expansion. The apparatus can be a plug, a bridge plug, a fracture plug, a packer, a permanent packer, a retrievable packer, a sump packer, and a sealbore packer. Additionally, the apparatus can include a completion assembly with packer and screen supported on the mandrel.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional Appl. 62/081,753, filed 19 Nov. 2014, which is incorporated herein by reference.

TECHNICAL FIELD

The present disclosure relates to the field of downhole tools, and in particular to downhole tools, such as bridge plugs, frac-plugs, and packers.

BACKGROUND ART

An oil or gas well includes a wellbore extending into a well to some depth below the surface. Typically, the wellbore is lined with tubulars or casing to strengthen the walls of the borehole. To strengthen the walls of the borehole further, the annular area formed between the casing and the borehole is typically filled with cement to set the casing permanently in the wellbore. Perforating the casing then allows production fluid to enter the wellbore and flow to the surface of the well.

Downhole tools with sealing elements, such as plugs or packers, are placed within the wellbore to isolate the production fluid or to manage production fluid flow through the well. For example, a bridge plug or a fracture plug placed within the wellbore can isolate upper and lower sections of production zones. Bridge plugs and frac-plugs create a pressure seal in the wellbore to allow pressurized fluids or solids to treat an isolated formation.

For their part, packers are typically used to seal an annular area formed between two co-axially disposed tubulars within a wellbore. For example, packers may seal an annulus formed between production tubing disposed within wellbore casing. Alternatively, packers may seal an annulus between the outside of a tubular and an unlined borehole. Routine uses of packers include the protection of casing from pressure, both well and stimulation pressures, as well as the protection of the wellbore casing from corrosive fluids. Other common uses include the isolation of formations or leaks within a wellbore casing or multiple producing zones, thereby preventing the migration of fluid between zones. Packers may also be used to hold kill fluids or treating fluids within the casing annulus.

These types of downhole tools are usually constructed of cast iron, aluminum, or other alloyed metals, but can be made of non-metallic materials, such as composite materials. A sealing member is typically made of a composite or synthetic rubber malleable material that seals off an annulus within the wellbore to prevent the passage of fluids. When the tool is activated, the sealing member is compressed or swells, thereby expanding radially outward from the tool to engage and seal with a surrounding casing or tubular. Conventional bridge plugs, fracture plugs, and packers typically comprise a synthetic sealing member located between upper and lower metallic retaining rings, commonly known as slips, that prevent the downhole tool from moving up or down in the wellbore.

As noted above, one type of downhole tool is a bridge plug, such as shown in a cutaway view in FIG. 1A. The bridge plug 10 has a mandrel 12, about which are disposed various elements typically formed of metal, but can be made of a composite material, such as is described in U.S. Pat. No. 7,124,831. Even when most of the bridge plug 10 is made of composite materials, the two slips 20 a-b may be made of metal, such as a ductile cast iron.

As shown, a sealing member 38 and other related elements 30 a-b are disposed about the mandrel 12. Axial force through the slips 20 a-b and the other elements 30 a-b compress the sealing member 38, causing it to expand and to seal with the surrounding tubular (not shown). The two slips 20 a-b, oriented opposite to each other, expand to engage with the surrounding tubular and help retain the downhole tool 10 in place. Boost forces from the sealing member 38 on the slips 20 a-b increase their holding ability.

The sealing elements 30 a-b each include a cone 32 and anti-extrusion rings 34. When pushed by the push ring 18 in the setting procedures, the first slip 20 a rides up the cone 32 to be wedged out against the surrounding tubular. At the same time, the slip 20 a and cone 32 are pushed along the mandrel 12 against the anti-extrusion rings 34 and the sealing element 38. On the opposite end, the second slip 20 b similarly rides up its cone 32 as the elements 30 a-b are pushed against the mule shoe 16 on the end of the mandrel 12.

Another downhole tool 10, such as a bridge plug, is shown in a cutaway view in FIG. 1B. This tool 10 uses a single bi-directional slip 20. Instead of confining a single sealing member with two slips, this single slip 20 is confined by two sealing systems 40 a-b.

As before, the downhole tool 10 uses a mandrel 12 having the remainder of the downhole tool 10 disposed about the mandrel 12. The single bi-directional slip 20 resists movement in either axial direction once activated by the sealing systems 40 a-b to engage with the surrounding tubular.

To provide sealing with the surrounding tubular, the downhole tool 10 uses the two sealing systems 40 a-b, one axially on either end of the slip 20. Each sealing system 40 a-b, in addition to sealing the downhole tool 10 with the surrounding tubular, also provides boost forces to the slip 20, increasing its ability to engage with the tubular and hold the downhole tool 10 in place under high pressure.

Each sealing system 40 a-b includes a sealing member 48, which is a malleable, synthetic element. In addition to the sealing member 48, each sealing system 40 a-b has a cone 42 and two sets of anti-extrusion rings 44. Axial force is applied to the sealing systems 40 a-b and slip 20 using a setting tool (not shown) in a manner similar to that discussed above.

Another type of downhole tool is a sump packer, which is used to locate the bottom of a screen assembly in a sand control or gravel pack completion. For example, FIG. 2 shows a typical gravel pack completion 50 having a sump packer 70 used for this purpose. Although the sump packer 70 can be used, other packers or plugs (e.g., bridge plug or cement plug) can be used.

In the cased hole C, the sump packer 70 is installed as a base for the gravel pack completion 50. The sump packer 70 can be run into the well on electric wireline prior to perforating the casing C. When set, the sump packer 70 positions at a point below the lowest planned perforation P. Typically, the sump packer 70 is a permanent seal bore type of packer, such as Weatherford's UltraPak Sump Packer or the Baker Model “D” or “F” Retainer Production Packer, although a retrievable sealbore packer could be used.

The sump packer 70 provides access to the bottom of the well C, which can act as a sump for debris left or dropped in the hole. The sump packer 70 also allows logging tools to be run below the producing interval.

The cased-hole gravel pack completion 50 has a retrievable sealbore packer 56 with a gravel pack extension 52, a crossover tool 55, and screen(s) 54 extending therefrom. The completion 50 is deployed into the cased well that has been perforated into the production zone, and the completion 50 at its distal end has a snap-latch assembly 60 that seals into the sump packer 70. The snap-latch assembly 60 provides a surface indication that the gravel pack completion 50 is properly located in the sump packer 70. With the completion 50 in place, the upper packer 56 is set, and the crossover tool 55 is manipulated to its various positions to pump the gravel as well as any other treatments. From that point, a tubing string T can install in the upper packer 56 to create a path for production fluid. Then, any of the other desired completion and production operations can be performed.

FIG. 2B shows an example of a sump packer 70 according to the prior art. The sump packer 70 includes a mandrel 72 having a polished bore 74. Inside the mandrel 72, the top of the bore 74 defines a locating shoulder and square thread 78. At the other end, lower slips 84 a rest against the mandrel 72 between a lower setting element 85 b and the mandrel's distal nose 76. In an opposing manner, upper slips 84 b rest against the mandrel 72 between an upper setting element 85 a and a setting sleeve 80 having a body lock ring 82. Between the setting elements 85 a-b is a packing element 90 disposed about the mandrel 72 to be compressed therebetween.

When the snap-latch assembly 60 as shown in FIG. 2C is inserted into the sump packer 70 (FIG. 2B), the assembly's end 66 seals inside the polished bore 74, latches 68 engage in the square thread 78, and the upper ledge engages the locating shoulder. The latches 68 have threaded fingers that collapse inward as the assembly 60 contacts the top of the sump packer 70. When the assembly 60 is fully lowered into the sump packer 70, the threaded fingers on the latches 68 expand and engage the left-hand square threads 78 in the top of the sump packer 70. About 2,000 pounds of set down weight may be required to snap into the packer 70, and about 8,000 to 12,000 pounds may be required to snap out.

In the setting process, the setting sleeve 80 on the sump packer 70 is then activated and moves downhole, while the body lock ring 82 prevents reverse movement. The setting assembly of the sump packer 70 is compressed by the slips 84 a-b riding up the ramps of the setting elements' cones 86 a-b and by the packing element 90 compressing between the setting elements 85 a-b and expanding outward to the casing. The setting elements 85 a-b can include anti-extrusion elements 88 a-b to limit the extrusion of the packing element 90 in the space between the setting elements 85 a-b and the surrounding casing. This can help assure a good seal in the annulus.

As can be seen above, downhole tools, such as packers, plugs, etc., can use a number of different elements systems having slips, setting elements (i.e., cones, anti-extrusion rings, etc.), and packing elements. In one continuing problem associated with conventional element systems of these types of downhole tools, the cones of the element systems can collapse. This can occur, for example, on both permanent and retrievable tools, such as packers. There is also a continuing desire to increase the contact area between the slips and cones of the element systems or at least to further distribute the cone-to-slip load over a larger area.

Attempts to design a convention downhole tool, such as a packer, capable of handling 10,000-psi or greater cone collapse pressure have been made, and testing has proven these attempts to be unsuccessful. One issue that prevents increased cone collapse pressures one conventional downhole tools is the limitations in the contact area between the slips and the cones when set into the tubular or casing. In some implementations, only a thin annular area exists between the downhole tool and the surrounding tubular that limits how much contact the cone can have to the slip.

Historically, the problem of increasing the cone collapse pressure has been solved by simply increasing the material strength of the components. Additionally, different slip configurations have been used, such as Halliburton's “barrel” slips, Baker Hughes' tangential slips or wedge slips, or Petrowell's multi-ramp slips. Some examples of different slip configurations are disclosed in U.S. Pat. Nos. 4,311,196; 5,884,699; 5,944,102; 6,302,217; 7,614,449; 7,690,424; and 8,567,510.

The subject matter of the present disclosure is directed to overcoming, or at least reducing the effects of, one or more of the problems set forth above.

SUMMARY OF THE DISCLOSURE

According to the present disclosure, an apparatus installs in a surrounding tubular. The apparatus has a mandrel, first and second opposing shoulders, a plurality of stacked rings, and a slip. The first and second opposing shoulders are disposed on the mandrel. At least the first opposing shoulders is movable toward the second opposing shoulder. The plurality of stacked rings are disposed about the mandrel and are spaced between the first and second opposing shoulders. First of the stacked rings decrease in spacing in response to the movement of the first opposing shoulder toward the second opposing shoulder, and second of the stacked rings expand outward from the mandrel in response to the decrease in spacing. The slip is disposed about the stacked rings and moves away from the mandrel toward the surrounding tubular in response to the outward expansion.

The slip can have a number of configurations as disclosed herein. The slip can have an outer surface with wickers for engaging the surrounding tubular. The slip can include a plurality of segments longitudinally arranged relative to the mandrel and disposed about the stacked rings.

A drive sleeve disposed on the mandrel move the first shoulder. A lock disposed between the drive sleeve and the mandrel can permit movement of the drive sleeve toward the second shoulder, but prevents reverse movement of the drive sleeve. The first shoulder can have a catch at least temporarily holding an end of the slip. For its part, the second shoulder can be a sleeve fixed on the mandrel.

The second of the stacked rings can be spaced between the first of the stacked rings. The first of the stacked rings can have at least one first ramped edge against which the second of the stacked rings adjacent thereto wedges. The second of the stacked rings can have at least one second ramped edge wedging against the at least one first ramped edge of the first of the stacked rings adjacent thereto.

The stacked rings can have a number of configurations, as disclosed herein. The stacked rings can be a full ring element defining a full circumference, a split ring element defining a split, a segmented ring element having a plurality of segments, and the like. Each of the stacked rings can be an individual ring element disposed about the mandrel. Alternatively, each of the stacked rings can be a strip coiled about a portion of the mandrel.

The stacked rings can include first and second outer rings each having a shoulder disposed adjacent one of the first and second shoulders disposed on the mandrel. The slip can have a central tab on an inner surface disposed toward the mandrel. The stacked rings in this case can include first and second inner rings each having a shoulder disposed adjacent a side of the central tab.

The spacings in between the stacked rings can expand the second of the stacked rings outward at one of the opposing shoulders before the other opposing shoulder. Also, the stacked rings can have contact angles disposed adjacent one another, and the contact angles can expand the second of the stacked rings outward at one of the opposing shoulders before the other opposing shoulder.

The apparatus can be a plug, a bridge plug, a fracture plug, a packer, a permanent packer, a retrievable packer, a sump packer, and a sealbore packer. According to the present disclosure, a setting sleeve disposed on the mandrel can compress against a packing element to expand outward toward the surrounding tubular.

According to the present disclosure, the apparatus disclosed above can further include a completion assembly that installs in the surrounding tubular. A distal end of the completion assembly is supported by the mandrel of the apparatus. In one example, the mandrel defines a throughbore, and the distal end of the completion assembly engages in the throughbore. A latch tool on the distal end can seal in the throughbore of the mandrel and can latching to the mandrel. In another example, the completion assembly can have a bull plug on the distal end. The completion assembly can include a packer disposed at a proximal end, an extension extending from the packer, and a screen disposed on the extension.

Methods of deploying and setting the apparatus disclosed above can involve deploying the apparatus in the surrounding tubular; and moving at least a first opposing shoulders disposed on the apparatus toward a second opposing shoulder disposed on the apparatus. The method decreases spacing of first of a plurality of stacked rings disposed on the apparatus between the first and second opposing shoulders in response to the movement and expands second of the stacked rings outward from the apparatus in response to the decrease in spacing. A slip disposed about the stacked rings engages toward the surrounding tubular in response to the outward expansion.

The foregoing summary is not intended to summarize each potential embodiment or every aspect of the present disclosure.

BRIEF DESCRIPTION OF DRAWINGS

The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate an implementation of apparatus and methods consistent with the present invention and, together with the detailed description, serve to explain advantages and principles consistent with the disclosed subject matter. In the drawings,

FIG. 1A illustrates a partial cross-sectional view of a bridge plug according to the prior art;

FIG. 1B illustrates a partial cross-sectional view of another bridge plug according to the prior art;

FIG. 2A illustrates a cased-hole gravel pack completion according to the prior art;

FIG. 2B illustrates a sump packer according to the prior art in partial cross-section;

FIG. 2C illustrates a snap-latch tool according to the prior art in partial cross-section;

FIGS. 3A-3B illustrate a downhole tool according to the present disclosure in partial cross-section in a run-in condition and a set condition, respectively;

FIGS. 3C-3D illustrate the downhole tool in partial cross-section revealing different configurations for stacked rings;

FIG. 4A illustrates another embodiment of the disclosed downhole tool in partial cross-section in the run-in condition;

FIG. 4B illustrates a more detailed view of the disclosed tool in the run-in condition;

FIG. 4C illustrates an isolated view of engagement of a setting sleeve with a slip segment on the disclosed tool;

FIG. 5A illustrates the disclosed downhole tool in partial cross-section in the set condition;

FIG. 5B illustrates a more detailed view of the disclosed tool in the set condition;

FIG. 6A illustrates a perspective view of an outer setting ring for the disclosed tool;

FIG. 6B illustrates a perspective view of an inner setting ring for the disclosed tool;

FIG. 7A illustrates perspectives view of two types of inner expansion rings for the disclosed tool;

FIG. 7B illustrates a perspective view of an outer expansion ring for the disclosed tool;

FIG. 8 illustrates a perspective view of a drive sleeve for the disclosed tool;

FIG. 9 illustrates a perspective view of a slip segment for the disclosed tool;

FIG. 10 illustrates a perspective view of a fixed sleeve for the disclosed tool;

FIG. 11A illustrates an embodiment of the disclosed tool used as a bridge plug to support a cased-hole gravel pack completion;

FIG. 11B illustrates an embodiment of the disclosed tool used as a sump packer to support a cased-hole gravel pack completion; and

FIG. 12 illustrates the disclosed tool as a bridge plug in partial cross-section.

DESCRIPTION OF EMBODIMENTS

FIGS. 3A-3B illustrate a downhole tool 100 according to the present disclosure in partial cross-section in a run-in condition. The downhole tool 100 can be configured as a bridge plug, a frac plug, a packer, or any other desired downhole packer tool. In a particular example, the downhole tool 100 can be a permanent sump packer used as a base for a cased-hole gravel pack completion.

The downhole tool 100 has a mandrel 102, first and second opposing shoulders 112 a-b, a plurality of stacked rings 130 a-b and 140 a-b, and a slip 150. The first and second opposing shoulders 112 a-b are disposed on the mandrel 110, and at least one of the opposing shoulders (e.g., the first shoulder 112 a) is movable toward the second opposing shoulder 112 b. These opposing shoulders 112 a-b can be part of sleeves 110 a-b disposed on the mandrel 102. In this context, the first sleeve 110 a can be a drive sleeve movable along the mandrel 102 toward the second, fixed sleeve 110 b. (FIG. 6 shows an isolated perspective view of a sleeve 110.)

The slip 150 includes a plurality of segments 152 that are axially aligned and disposed about the stacked rings 130 a-b, 140 a-b. The exposed surfaces of the slip segments 152 have wickers, teeth, or the like for engaging the surrounding tubular, casing, or the like. The inner surface of the slip segments 152 can have a central tab 158 for stabilizing the segments 152 on the tool 100. In particular, the central tab 158 has square shoulders that set against adjacent rings (e.g., 140 a).

The stacked rings 130 a-b, 140 a-b are disposed about the mandrel 102 and are spaced between the first and second opposing shoulders 112 a-b. The stacked rings 130 a-b, 140 a-b decrease in spacing in response to the movement of the first opposing shoulder 112 a toward the second opposing shoulder 112 b, and at least some of the stacked rings (e.g., 140 a-b) expand outward from the mandrel 102 in response to the decrease in spacing.

In particular, first rings 130 a-b are disposed about the mandrel 102 and are spaced between the first and second opposing shoulders 112 a-b of the sleeves 110 a-b. Second rings 140 a-b are also disposed about the mandrel 102 as well, but they are spaced in between each of the first rings 130 a-b. The slip 150 with its segments 152 is disposed on the first and second rings 130 a-b, and 140 a-b.

During activation, the drive sleeve 110 a is moved toward the fixed sleeve 110 b. Activation can be achieved in several known ways—some of which are disclosed herein. The first rings 130 a-b decrease in spacing in response to the movement of the drive sleeve 110 a toward the opposing sleeve 110 b, and the second rings 140 a-b expand outward from the mandrel 102 in response to the decrease in spacing of the first rings 130 a-b. Finally, the slip segments 152 move away from the mandrel 102 toward the surrounding tubular in response to the outward expansion of the second rings 140 a-b.

FIG. 3C illustrate the downhole tool 100 in partial cross-section revealing how the stacked rings can be configured as individual rings 130 a-b, 140 a-b alternatingly stacked on the outside of the mandrel 102. A gap G is present between inner expansion rings 140 a where the central tabs 158 of the segments 152 positions.

An alternative configuration is shown in FIG. 3D. Here, the stacked rings can be configured as strips 135 and 145 (wires, springs, or the like) alternatingly coiled about the mandrel 102 to form the various rings 130 a-b, 140 a-b. The lengths of the strips 135 and 145 may not fully encompass the expanse between the opposition shoulders 112 a-b so that space can be provided for at least some of the ends of these coiled strips 135 and 145 to accommodate spiraled movement of the strips during activation.

Again, a gap G is present where the central tabs 158 of the segments 152 positions. The strips 135, 145 at one end of the slip 150 can be coiled in one direction, and the strips 135, 145 at the other end can be similarly coiled in the same direction. Alternatively, the strips 135, 145 can be coiled in opposing directions to one another.

Either of these configurations in FIGS. 3C-3D can achieve the same results during activation. As the opposing shoulders 112 a-b are brought closer together, the expansion rings 140 a-b (either as individual rings or parts of a coil) can expand outward and push the slip segments 152 toward the surrounding tubular.

During activation, a lock 114, such as a body lock ring or other mechanism, disposed between the drive sleeve 110 a and the mandrel 102 permits the movement of the drive sleeve 110 a toward the fixed sleeve 110 b, but the lock 114 prevents reverse movement of the drive sleeve 110 a. In this way, the tool 100 will not unset once setting forces cease. Once the tool 100 is activated (i.e., the second rings 140 a-b are expanded, the slip segments 152 are engaged, etc.), the tool 100 can seal the annulus between the mandrel 102 and the surrounding tubular or casing.

The downhole tool 100 can be installed in the wellbore with any desired non-rigid system, such as electric wireline or coiled tubing. A setting tool (not shown), such as a Baker E-4 Wireline Setting Assembly commercially available from Baker Hughes, Inc., can connect to an upper portion of the mandrel 102. Specifically, an outer movable portion of the setting tool is disposed about the outer diameter of the mandrel 102, abutting the end of the drive sleeve 110 a. An inner portion of the setting tool can affix to the mandrel 102. The setting tool and the downhole tool 100 are then run into the well casing to the desired depth where the downhole tool 100 is to be installed.

To set or activate the downhole tool 100, the mandrel 102 is held by the wireline, through the inner portion of the setting tool, as an axial force is applied through the outer movable portion of the setting tool to the drive sleeve 110 a, which transfers axial force from the setting tool to the element system. In particular, the axial force causes the outer portions of the downhole tool 100 to move axially relative to the mandrel 102. The force asserted against the drive sleeve 110 a is transmitted by the shoulder 112 a. An equal and opposite force is asserted by the fixed sleeve 110 b on the other end of the downhole tool 100. The force from both ends is transmitted to the element system, which causes the slip 150 and second rings 140 a-b to expand and set against the surrounding tubular.

The segments 152 of the slip 150 can be initially interconnected together and may fracture under radial stress. The slip 150 can have a plurality of recessed grooves, allowing the slip segments 152 to fracture along the grooves. Alternatively, the segments 152 may already be independent.

An outer surface of the slip 150 can include outwardly, extending wickers, comprising serrations or edge teeth. The wickers can be arranged with a first set oriented toward the drive sleeve 110 a, to resist uphole axial movement, and the wickers can be arranged with a second set oriented toward the fixed sleeve 110 b, to resist downhole axial movement. Any number, shape, and configuration of wicker can be used as desired.

When set, the downhole tool 100 can acts as a packer with the slip 150 fixing the tool 100 in place. The stacked contact between the rings 130 a-b, 140 a-b and the radial forces they place on the outside of the mandrel 102 and the inside of the slip 150 can also act as a fluid seal in the annular space between the mandrel 102 and the surrounding casing, although the fluid seal for the downhole tool 100 can be provided by a separate packing element (not shown) on the mandrel 102.

Any fluid sealing provided at the rings 130 a-b, 140 a-b and slip 150 can be achieved by encasing the components in an elastomer. Alternatively, the sealing can be achieved in part by the stacked fit between the rings 130 a-b, 140 a-b. If the rings 130 a-b, 140 a-b are metallic, then the sealing can be a metal-to-metal seal between the interfacing surfaces. If one or the other of the rings 130 a-b, 140 a-b are composed of another malleable or low yield material (e.g., plastic, elastomer, 4140 stainless steel, etc.), then sealing between the stacked rings 130 a-b, 140 a-b can be comparably made between the interfacing surfaces. In fact, the splits 144 if present in the expansion rings 140 a-b can be misaligned, creating a tortuous path capable of sealing. Similarly, if the expansion rings 140 a-b are composed of a compressible material, then the splits 144 if present in these rings 140 a-b can close to create the desired sealing. Finally, other forms of sealing, such as an independent packing element or seal, could be used elsewhere on the tool 100 in relation to the slip 150 and stacked rings 130 a-b, 140 a-b depending on the implementation.

Turning now to Figurers 4A through 10, details of another embodiment of the disclosed tool 100 are discussed. FIG. 4A illustrates the disclosed downhole tool 100 along with a setting tool in partial cross-section in the run-in condition, and FIG. 4B illustrates a more detailed view of the disclosed downhole tool 100 in the run-in condition.

Similar components have the same reference numbers as in the previous embodiment. Again, the downhole tool 100 has a mandrel 102, first and second opposing shoulders 112 a-b, a plurality of stacked rings (i.e., first setting rings 130 a-b and second expansion rings 140 a-b), and a slip 150. At least the first shoulder 112 a on the drive sleeve 110 is movable toward the second opposing shoulder 112 b on the fixed sleeve 110 b.

As shown, the mandrel 102 can define a throughbore 104, although this is not strictly necessary depending on the purpose of the tool 100. In the present context, the tool 100 is shown as a sump packer. Therefore, the mandrel 102 defines a wide cylinder close to the inner dimension of the surrounding casing. Additionally, the mandrel's throughbore 104 can define a wide inner dimension and can be a polished bore, such as used for a sump packer for sealing with a latch assembly.

The setting rings 130 a-b are disposed about the mandrel 102 and are spaced between the opposing shoulders 112 a-b of the sleeves 110 a-b. The expansion rings 140 a-b are also disposed about the mandrel 102 as well, but they are spaced in between each of the setting rings 130 a-b. The slip 150 with its segments 150 is disposed on the rings 130 a-b, and 140 a-b.

The slip 150 includes a plurality of segments 152 that are axially aligned and disposed about the rings 130 a-b, 140 a-b. (FIG. 9 shows an isolated perspective view of a segment 152 of the slip 150). The exposed surfaces of the slip segments 152 have wickers, teeth, or the like for engaging the surrounding tubular. The inner surface of the slip segments 152 can have a central tab 158 for stabilizing the segments 152 on the tool 100, as will be described below.

As shown in the detailed view of FIG. 4C, each end of the opposing shoulders (e.g., 112 b) can have a catch 113, tooth, or the like to engage an end of a slip segment 152. Other ways of fixing the segment 152 can be used, including shear pins, shear screws, frangible bands, etc. The catches 113 on the ends of the segments 152 hold the slip 150 and other elements together during run-in, as shown in FIGS. 4A-4B. This can help prevent premature setting and can retain the slip segments 152 during tripping downhole.

As noted above, activation of the tool 100 can be achieved in several ways. In the current embodiment as best shown in FIGS. 4A and 5A, the mandrel 102 of the tool 100 has a setting sleeve 160 moveably disposed toward the uphole end near the drive sleeve 110 a. The setting sleeve 160 includes a body lock ring 162 or other mechanism that allows movement of the sleeve 160 toward the drive sleeve 110 a, but prevents the reverse. A packing element 165 on the setting sleeve 160 can be expanded to seal with the surrounding tubular or casing C. Any of the various types of packing elements can be used, and only a schematic arrangement is shown here. In general, the packing element 165 can include an elastomer for sealing, a cone and wedge ring arrangement, or any other acceptable arrangement.

As the setting sleeve 160 is freed with downhole movement (by shearing pins or the like), the setting sleeve 160 moves along the mandrel 102 with the sleeve's body lock 162 preventing reverse movement. The packing element 165 expands outward against the casing C, and the setting sleeve 160 moving along the mandrel 102 eventually pushes the drive sleeve 110 a, which then activates the slip 150, setting rings 130 a-b, and expansion rings 140 a-b to set the slip 150 outward against the casing C.

In particular and as discussed previously, the drive sleeve 110 a during activation is moved toward the fixed sleeve 110 b. (FIG. 8 illustrates a perspective view of the drive sleeve 110 a for the disclosed tool 100). Once the drive sleeve 110 a is moved, the catch 113 near the sleeve's shoulder 112 a can disengage from the slip segments (152), and the shoulder 112 a can push against the rings (130 a-b, 140 a-b). Meanwhile, the body lock ring 114 on the inside of the drive sleeve 110 a can engage a threaded surface on the tool's mandrel (102) to lock forward progress of the sleeve 110 a.

At the opposite end of the tool 100, the fixed sleeve 110 b, which is shown in an isolated view in FIG. 10, allows the rings (130 a-b, 140 a-b) to press against its shoulder 112 b. Likewise, shifting of the slip segments (152) disengages their ends from the catch 113 near this second shoulder 112 b. Pockets 115 disposed around the outside of the fixed sleeve 110 b can accommodate anti-rotation lugs (117; FIGS. 4B, 5B) that engage in outer slots on the mandrel 102 and are covered by a cover (119; FIGS. 4B, 5B) on the fixed sleeve 110 b.

During activation as best shown in FIG. 5B, the setting rings 130 a-b decreases in spacing in response to the movement of the drive sleeve 110 a toward the opposing sleeve 110 b, and the expansion rings 140 a-b expand outward from the mandrel 102 in response to the decrease in spacing of the setting rings 130 a-b. Finally, pushed outward with the expansion rings 140 a-b, the slip segments 152 move away from the mandrel 102 toward the surrounding casing in response to the outward expansion of the expansion rings 140 a-b.

Thus, during activation, the setting and expansion rings 130 a-b, 140 a-b begin to make contact, and the setting rings 130 a-b force the expansion rings 140 a-b outward due to the incline ramp faces on each setting ring 130 a-b. In turn, as the expansion rings 140 a-b are forced outward, the outer dimension of the rings 140 a-b makes contact on the slip's inside surfaces to force the slip segments 152 outward to bite into the surrounding casing C.

Being stacked along the outside of the mandrel 120, the setting and expansion rings 130 a-b, 140 a-b increase the contact area between the rings 130 a-b, 140 a-b and slip 150. The stacking of the rings 130 a-b, 140 a-b also distributes load over a larger area outside the mandrel 102 and inside the slip 150. Additional rings can be stacked to increase the contact area if the slip 150 needs to be qualified for a higher pressure or load.

Each ring 130 a-b, 140 a-b transfers the applied axial force to radial expansion toward the inner surface of the surrounding casing. The expansion rings 140 a-b flow and expand across the ramped surfaces of the setting rings 130 a-b, applying a collapse load through the setting rings 130 a-b on the mandrel 102, which helps prevent slippage of the system one activated. The collapse load also prevents the rings 130 a-b, 140 a-b from rotating on the mandrel 102.

As shown in isolated detail in FIGS. 6A-6B, the setting rings 130 a-b can be solid rings 132 that slide onto the outer surface of the mandrel (102), although split or even segmented rings could be used. These setting rings 130 a-b can be composed of a rigid material, such as a metal, plastic, etc. The outer ones of these setting rings (i.e., 130 a in FIG. 6A) can have shouldered edges 138 for engaging against the opposing shoulders (112 a-b) of the sleeves (110 a-b). However, the remaining interior edges 136 of the rest of the setting rings 130 a-b are ramped or sloped outward.

As shown in isolated detail in FIGS. 7A-7B, the second expansion rings 140 a-b can be split rings 142 having splits 144. These expansion rings 140 a-b can be composed of a rigid material, such as a metal, plastic, etc. Alternatively, the expansion rings 140 a-b can be composed of compressible/expandable material, such as an elastomer, plastic, etc., and the expansion rings 140 a-b may not include a split.

The inner ones of these expansion rings (i.e., 140 a in FIG. 7B) can have shouldered edges 148 for engaging against the opposing sides of the central tab (158) on the slip segments (152). However, the remaining interior edges 146 of the rest of the expansion rings 140 a-b are ramped or sloped inward to wedge against the ramped edges 136 on adjacent first rings 130 a-b.

As an alternative to the split ring, any of the expansion rings 140 b′ can be a segmented ring having a number of segments 143. This configuration can also be used for any of the other rings 130 a-b, 140 a disclosed herein.

The contact angles of the ramped edges 136, 146 for the rings 130 a-b, 140 a-b can be configured as desired to achieve desired wedging. The contact angles of the edges 136, 146 can be comparable for both types of rings 130 a-b, 140 a-b, or the angles for the different rings 130 a-b, 140 a-b can be differently configured. Likewise, the angles for the edges 136, 146 of each ring 130 a-b, 140 a-b can all be similarly configured along the length of the element system from the uphole end of the slip 150 to the downhole end of the slip 150.

Alternatively, the contact angles of the edges 136, 146 can be configured along the length of the elements so that the slip segments 152 initially set outward at their uphole end first and then set toward their downhole end. The reverse configuration could also be used. As an alternative or in addition to the changing angles along the length of the element system, the geometry of the rings 130 a-b, 140 a-b can be different from one end of the element system to the other to create a setting sequence from one end of the slip 150 to the other. In other variations to achieve a desired setting sequence, slots can be added, the materials can differ, thinner cross-sections can be provided, and the like to some of the rings 130 a-b, 140 a-b.

The disclosed tool 100 can be used in any packer application that requires holding high loads in thin cross-section designs. As noted herein, the disclosed tool 100 can be a plug. To that end, the tool 100 can be used with a completion assembly having a distal end supported by the tool 100. As depicted in FIG. 11A, for example, a gravel pack completion 250 can have a retrievable sealbore packer 256 with a gravel pack extension 252, crossover tool 255, and screen(s) 254 extending therefrom. At its distal end, the gravel pack completion 250 can have a bull plug 258 disposed at the bottom of the screen(s) 254.

Before the completion 250 is deployed, the disclosed tool 100 configured as a bridge plug 100 is set in the casing C at a suitable location using any of the various setting techniques. The completion 50 is then deployed into the cased well, and the bull plug 258 can be supported on the disclosed tool 100 configured as the bridge plug. In this arrangement, the mandrel 102 of the tool 100 may or may not have a flow passage therethrough.

In another implementation for supporting the gravel pack completion 250, the disclosed tool 100 can be used as a sump packer. As depicted in FIG. 11B, the mandrel 102 of the disclosed tool 100 as a sump packer defines a throughbore. As before, the completion 250 can have a retrievable sealbore packer 256 with a gravel pack extension 252, a crossover tool 255, and screen(s) 254 extending therefrom. At its distal end, the gravel pack completion 250 can have a snap-latch tool 260 installing in the throughbore 104 of the mandrel 102. The snap-latch tool 260 has seals sealing in the throughbore 104 of the mandrel 102 and has a latch latching to the mandrel 102. Although not shown, it will be appreciated that the disclosed tool 100 can have a setting sleeve (e.g., 160) and other features similar to those discussed above with reference to FIGS. 4A and 5A.

The snap-latch tool 260 provides a surface indication that the gravel pack completion 250 is properly located in the sump packer 100. With the completion 250 in place, the upper packer 256 is set, and the crossover tool 255 is manipulated to its various positions to pump gravel as well as any other treatments into the annulus and through the perforations. From that point, a tubing string T can install in the upper packer 256 to create a path for production fluid. Then, any of the other desired completion and production operations can be performed.

Finally, as noted previously, the disclosed tool 100 can be used as a number of downhole packer tools or the like. As an example, FIG. 12 illustrates the disclosed tool 100 as a bridge plug in partial cross-section. The bridge plug 100 has a mandrel 102 having a packing element 109 and setting elements 110-150. The packing element 109 can be disposed on the mandrel 102 near the shoe 106 and can include some conventional components, such as anti-extrusion elements 30 a-b and a packer 38. The anti-extrusion elements 30 a-b can have various backup rings 34 and the like. The setting elements 110-150 are similar to those disclosed herein and can be disposed about the mandrel 102 between the packing element 109 and a push ring 108. Setting of the packing element 109 and the setting elements 110-150 can be achieved by axial force applied against the push ring 108 and compressing the components against the shoe 106 on the held mandrel 102.

The foregoing description of preferred and other embodiments is not intended to limit or restrict the scope or applicability of the inventive concepts conceived of by the Applicants. More or less rings 130 a-b, 140 a-b can be used. The rings 130 a-b, 140 a-b can be disposed along a length of the mandrel 102 greater or shorter than the extent of the slip 150. All of the rings 130 a-b, 140 a-b preferably have ramped surfaces, although this is not strictly necessary if the alternating expansion rings 140 a-b even with a different cross-section can ride up on the setting rings 130 a-b with a different cross-section.

It will be appreciated with the benefit of the present disclosure that features described above in accordance with any embodiment or aspect of the disclosed subject matter can be utilized, either alone or in combination, with any other described feature, in any other embodiment or aspect of the disclosed subject matter.

In exchange for disclosing the inventive concepts contained herein, the Applicants desire all patent rights afforded by the appended claims. Therefore, it is intended that the appended claims include all modifications and alterations to the full extent that they come within the scope of the following claims or the equivalents thereof. 

What is claimed is:
 1. An apparatus installing downhole in a surrounding tubular, the apparatus comprising: a mandrel; first and second shoulders disposed on the mandrel, at least the first shoulder being movable toward the second shoulder; a plurality of stacked rings disposed about the mandrel and spaced between the first and second shoulders, a first of the stacked rings decreasing in spacing in response to the movement of the first shoulder toward the second shoulder, a second of the stacked rings expanding outward from the mandrel in response to the decrease in spacing; and a slip disposed on the stacked rings, the slip being movable away from the mandrel toward the surrounding tubular in response to the outward expansion.
 2. The apparatus of claim 1, wherein the apparatus is selected from the group consisting of a plug, a bridge plug, a fracture plug, a packer, a permanent packer, a retrievable packer, a sump packer, and a sealbore packer.
 3. The apparatus of claim 1, wherein the slip comprises an outer surface having wickers engageable with the surrounding tubular.
 4. The apparatus of claim 1, wherein the slip comprises a plurality of segments being arranged longitudinally relative to the mandrel and being disposed about the stacked rings.
 5. The apparatus of claim 1, wherein the first shoulder comprises a drive sleeve disposed on the mandrel and movable thereon.
 6. The apparatus of claim 5, further comprising a lock disposed between the drive sleeve and the mandrel, the lock permitting movement of the drive sleeve toward the second shoulder and preventing reverse movement of the drive sleeve away from the second shoulder.
 7. The apparatus of claim 1, wherein the second opposing comprises a sleeve fixed on the mandrel.
 8. The apparatus of claim 1, wherein the second of the stacked rings is spaced in between the first of the stacked rings, the second of stacked rings expanding outward from the mandrel in response to the decrease in spacing of the first of the stacked rings.
 9. The apparatus of claim 8, wherein the slip is disposed about at least the second of the stacked rings, the slip being movable away from the mandrel toward the surrounding tubular in response to the outward expansion of the second of the stacked rings.
 10. The apparatus of claim 1, wherein the first of the stacked rings comprises at least one first ramped edge against which the second of the stacked rings adjacent thereto wedges.
 11. The apparatus of claim 10, wherein the second of the stacked rings comprises at least one second ramped edge wedging against the at least one first ramped edge of the first of the stacked rings adjacent thereto.
 12. The apparatus of claim 1, wherein the stacked rings comprises at least one of a split ring element defining a split; a segmented ring element having a plurality of segments; a full ring element defining a full circumference; an individual ring element disposed about the mandrel; a strip coiled about a portion of the mandrel; a compressible material; and a rigid material.
 13. The apparatus of claim 1, wherein the stacked rings comprise first and second outer rings each having a third shoulder disposed adjacent one of the first and second shoulders disposed on the mandrel.
 14. The apparatus of claim 1, wherein the slip comprises a central tab disposed on an inner surface of the slip toward the mandrel, and wherein the stacked rings comprise first and second inner rings each having a third shoulder disposed adjacent a side of the central tab.
 15. The apparatus of claim 1, wherein the first shoulder comprises a catch at least temporarily holding an end of the slip.
 16. The apparatus of claim 1, wherein the stacked rings have different spacings between one another, whereby the second of the stacked rings at one of the first and second shoulders expands outward before the second of the stacked rings at the other of the first and second shoulder.
 17. The apparatus of claim 1, wherein the stacked rings have different contact angles disposed adjacent one another, whereby the second of the stacked rings expands outward at one of the first and second shoulders before the second of the stacked rings at the other of the first and second shoulder.
 18. The apparatus of claim 1, further comprising: a packing element disposed on the mandrel adjacent the first shoulder; and a setting sleeve disposed on the mandrel adjacent the packing element, the setting sleeve movable on the mandrel toward the first shoulder and expanding the packing element outward toward the surrounding tubular.
 19. The apparatus of claim 1, further comprising a completion assembly installing in the surrounding tubular and having a distal end supported by the mandrel of the apparatus.
 20. The apparatus of claim 19, wherein at least one of: the distal end engages in a throughbore defined in the mandrel; the distal end comprises a seal sealing in a throughbore of the mandrel; the distal end comprises a latch latching to the mandrel; and the distal end comprises a bull plug.
 21. The apparatus of claim 19, wherein the completion assembly comprises: a packer disposed toward a proximal end of the completion assembly; and a screen disposed on the assembly between the packer and the distal end.
 22. A method of installing an apparatus downhole in a surrounding tubular, the method comprising: deploying the apparatus in the surrounding tubular; moving at least a first shoulder disposed on the apparatus toward a second shoulder disposed on the apparatus; decreasing spacing of first of a plurality of stacked rings disposed on the apparatus between the first and second shoulders in response to the movement; expanding second of the stacked rings outward from the apparatus in response to the decrease in spacing; and engaging a slip disposed on the stacked rings toward the surrounding tubular in response to the outward expansion. 